Junior Subordinated Debentures Summary (Details) (USD $)	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2012 ASBC Capital I [Member]	Dec. 31, 2011 ASBC Capital I [Member]	Sep. 30, 2012 SFSC Capital I [Member]	Dec. 31, 2011 SFSC Capital I [Member]	Sep. 30, 2012 SFSC Capital II [Member]	Dec. 31, 2011 SFSC Capital II [Member]
Subordinated Borrowing [Line Items]
Common securities	$ 4,639,000	$ 5,412,000	$ 464,000	$ 464,000	$ 464,000	$ 464,000
Junior subordinated debentures, at par	$ 150,000,000	$ 175,000,000	$ 15,000,000	$ 15,000,000	$ 15,000,000	$ 15,000,000
Interest Rate of Junior SFSC subordinated debt	Fixed	Fixed	L+3.45	L+3.45	L+2.80	L+2.80
Contractual rate	7.625%	7.625%	3.88%	3.91%	3.25%	3.23%
Maturity date	Jun. 01, 2032	Jun. 01, 2032	Nov. 01, 2032	Nov. 01, 2032	Apr. 01, 2034	Apr. 01, 2034